Loud-speaker and sound-reproducing unit



June 18, 1929.-

C. E. SEMPLE, JR

LOUD SPEAKER AND SOUND REPRODUCING UNIT Filed Juiy 19/ 1926 2 Sheets-Sheet l June 18, 1929. c, $EMPLE JR 1,718,009

LOUD SPEAKER AND SOUND REPRODUCING UNIT gwuentoz Patented June 18, 1929.

PATENT GFFICE.

CHARLES E. SEMPLE, 53., F YOUNGSTOWN, OHIO, ASSIGNOR T0 CLARAVOX, INC. 0F

CANTON, OHIO, A CORPORATION 9F OHIO.

LOUD-SPEAKER AND SOUND-REIPRUDUCING UNIT.

Application filed July 19, 1926. Serial No. 128,309.

My invention relates to loud speakers and sound reproducing units for use in the rad1o, telephone, phonograph, and other all1ed arts; and more particularly to a loud speaker including a diaphragm connected to the armature of an electro-magnetic sound reproducing unit which may be actuated by relatively Weak fluctuating currents.

Loudspeakers of this type at present in use are generally bulky, and are not umformly satisfactory in their reproductions over the full range of audible waves.

One object of the present improvements is to provide an improved and compact construction and arrangement of diaphragm and amplifying chamber, whereby the vibrations of sound transmitted to the diaphragm are e'liiciently and accurately amplified and resonated by the diaphragm and and the amplifyin chamber; and these objects are attained %y the use of a construction and arrangement which may be described in gen eral terms as including a preferably modified diaphragm functionally connected wlth a bell amplifying section.

A further object of the present improvements is to provide for the transmission of sound vibrations to the improved preferably modified diaphragm, an improved electromagnetic sound reproducing unit of novel construction and arrangement, whereby its operation is characterized by low magnetic losses, and whereby positive stablhzing means are provided for the armature of the unit for enabling rapid and accurate adjustment of the armature in the magnetic field.

Further objects of my invention are to provide a loudspeaker and unit therefor, which includes simply arranged and accessible parts for enabling easy assembly and adjustment, and which are adapted to economical mass production.

For the attainment of these and other objects, my invention includes the nature, the mode of operation, and the details of construction 'ofthe elements herein described, claimed, and illustrated in the accompanying drawings, forming part hereof, in which Figure 1 is an elevation view of a preferred embodiment of my improved loud speaker and sound reproducing unit;

Fig. 2, a transverse cross-sectionthereof as on line 2-2, Fig. 1;

Fig. 3, an elevation of the sound reproducing unit detached from a loud speaker diaphragm and bell;

Fig. 4, a plan View thereof;

Fig. 5, a sectional view as on line -5, Figs. 3 and 4; and

Fig. 6, a detached perspective vievc of the armature, longitudinal pivotal support, and spring stabilizer.

The preferred embodiment of my invention includes a bell section functionally connected with a modified diaphragm section 11. The modified diaphragm section preferably includes a base frus'trum section 12 connected with an inverted apex section 13, but the apex section might be used as a straight cone as indicated in the dotted'lines at 14 rather than in the inverted position.

The extreme tip 15 of the cone is connected by the'link 16 with the armature 17 of the sound reproducing unit 18 mounted on a suitable support 19 which may be preferably se cured to the bell section, as by screws 19. The link 16 may be rigid throughout its'entire length but it is preferably connected to the armature by a short flexible end piece 20 disposedbetween the end of the link and armature.

The sound reproducing unit 18 preferably includes four permanent magnets 21 and 21, the pair 21 having the same polarity indicated and the pair 21 having the same polarity indicated and opposite the polarity of the pair' 21, and each pair being secured to a base 19 as by a screw 2 in cooperation with a plate 23, and the screws 22 may likewise serve to secure the unit to the support 19.

As best illustrated in Fig. 5, the magnets are transversely angled with respect to each,

other as at 24, as by means of spacers 25 and 26 of diflerent thicknesses, the spacer 25 be ing preferably the thinner.

Adjacent the spacers 25 upwardly extending brackets 27 secured to the support are provided for mounting the longitudinal axial support 28 for the armature l7 and rigidly secured thereto.

For stabilizing thearmature a preferably tlehaped spring 29 is rigidly secured at its middle as at 30 with the axial armature support, and adjustably mounted at the outer ends of its legs 29* and 29 as by screws 31 passing through apertures 29*" and 29" in the legs 29 and 29 and screwed into outwardly projecting lugs 32 on the bracket 27.

By this construction the armature is arranged to oscillate about an axis parallel to the longitudinal axis of the magnets, rather than about an axis at right angles thereto as disclosed in the prior art.

For enabling easy oscillation of the armature, the longitudinal axial support 28 is preferably reduced in cross section as at 33 be.- yond each longitudinal end of the armature 17 and is then enlarged in cross section as. at ends 34, which are provided with apertures 35 for adjustably mounting the pivotal support 28 to the brackets 27, as by means of screws '36 adjustably passing through apertures 37 in each bracket 27, and through the apertures 35 in each end 34 of the longitudinal armature axial support 28, for screwing into a nut plate 38, and preferabl being provided beneath their heads with a washer plate 39.

For adjusting the stabilizing springs as aforesaid, the screws 31 pass through the apertures 29 and 29 in the ends 29 and 29 of the spring, and the apertures 29 and 29" are slightly larger than the screws 31.

Likewise theapertures 37 in the brackets 27 are slightly larger in diameter than the screws 36 fitting therein.

By these means and by the extension of the U-spring legs 29 and 29 'laterally from the axial support 28 and angular thereto, the armature may be rapidly and accurately adj usted angularly, laterally, and vertically.

For oscillating the armature in conformity to the waves which it is desired to reproduce, a coil 40 is located adjacent to and preferably encircling the armature 17, and the. axis of the coil ispreferably at right angles to the longitudinal axial support of the preferably fiat armature 17. The coil 40 may be connected in a. circuit, not shown, and may have impressed or induced fluctuating voice currents flowing therethrough.

The polarity of the two pairs of magnets 21 and 21 is preferably as indicated in Fig. 3; that is to say, the visible pole of the upper magnet 21 is north, and the visible pole of the lower ma'g'net 21 is south, and the visible pole of the up er magnet 21 is north, and the visible pole o the lower magnet 21 is south.

In other words, as viewed in Fig. 3, there are two upper visible north poles and two lower visible south poles for the four magnets, although like results would be obtainable if the two upper visible poles were south and the two lower visible poles were north.

Likewise with the arrangement illustrated in Fig. 3, the upper poles adjacent the armature support are both south poles and the lower poles adjacent the armature support are both north poles.

When a'current flows in the coil 40, a magnetic field will be created in the armature 17, and this field-will run through the armature substantially crosswise of the axial armature support 28, thereby creating north and south magnetic poles in the armature, which may be 'for a certain direction of current flow, as indicated in Fig. 6, with the north pole adjacent the armature support and the south pole at the opposite end thereof.

If a current flows in the coil to create the poles in the armature indicated in Fig. 6, the upper north poles visible in Fig. 3 will at tract the'outer end of the armature having the south poles created therein, and the lower visible south poles of the magnets will repel the outer south pole end of the armature.

Likewise the upper south pole ends of the magnets adjacent the axial support will attract the north pole end of the armature adjacent the axial support, and the lower north pole ends of the magnets adjacent the axial support will repel the north pole end of the armature adjacent the axial support.

That is to say, the magnetic lines of force extending between the north and south poles of the magnets cooperate with the magnetic poles set up in the armature by a flow of current through the coil to oscillate the armature about its axial support, and these lines of force and the magnetic poles are all on the same side of the axial armature support.

A fluctuating current flowing through the coil, such as a fluctuating current corresponding to audible waves, will obviously consecutively reverse the polarity of the armature, whereby the magnets will have a successively reversing attraction and repulsion for the armature ends, and will thereby oscilla the armature about its axial supportin conformation'with the fluctuations of the currents flowing through the coil, and these oscillations will be transmitted to the diaphragm through the flexibly connected link 16.

The provision of the flexible connection 20 for the link 16 prevents the bowing effect which would otherwise be set up in the link 16 by the oscillations of the armature 17, which bowing would create undesirable vibrations in the diaphragm.

I claim:

1. A sound reproducing apparatusincluding an armature, means supporting the armature for oscillating movement about an axis, a coil adjacent the armature and operative by a current flowing therethrough to create a magnetic field in the armature, the field running through the armature substantially cross-wise of the axis, and thereby creating north and south magnetic poles in the armature at one side of the axis, a magnet arranged above the armature and a magnet arranged below the armature and the poles of the magnets being located close to the poles of the armature, means for stabilizing the armature between the magnet poles, and means for connecting the armature to a diaphragm.

:2. A sound reproducing apparatus including a substantially rigid armature, means supporting the armature for oscillating movement about an axis, electromagnetic means including a plurality of magnets for oscillating the armature about the axis, the magnets each including a plurality of poles,

and the plane of the poles of one magnet being transversely angled with respect to the plane of the poles of another magnet and in 10 tersecting adjacent the axis.

In testimony that I claim the above, I have hereunto subscribed my name.

CHARLES E. SEMPLE, JR. 

